/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.apache.jackrabbit.webdav.observation;

import org.apache.jackrabbit.webdav.DavException;
import org.apache.jackrabbit.webdav.DavResource;

/**
 * <code>ObservationResource</code> extends the {@link DavResource} interface by
 * observation relevant METHODS.
 */
public interface ObservationResource extends DavResource {

	public String METHODS = "SUBSCRIBE, UNSUBSCRIBE, POLL";

	/**
	 * Initializes this resource.
	 * 
	 * @param subsMgr
	 *            subscription manager object
	 */
	public void init(SubscriptionManager subsMgr);

	/**
	 * Retrieve the list of events that where recorded for the event listener
	 * with the given SubscriptionId.
	 * 
	 * @param subscriptionId
	 *            as present in the
	 *            {@link ObservationConstants#HEADER_SUBSCRIPTIONID
	 *            SubscriptionId} header.
	 * @param timeout
	 *            as present in the
	 *            {@link ObservationConstants#HEADER_POLL_TIMEOUT} header or 0
	 *            (zero) if none is present.
	 * @return <code>EventDiscovery</code> object
	 */
	public EventDiscovery poll(String subscriptionId, long timeout)
			throws DavException;

	/**
	 * Subscribe this resource for event listening defined by the specified
	 * subscription info. A subscriptionId may be specified in case an existing
	 * subscription should be modified.
	 * 
	 * @param info
	 *            <code>SubscriptionInfo</code> object as defined by the request
	 *            body and headers.
	 * @param subscriptionId
	 *            or <code>null</code> if the
	 *            {@link ObservationConstants#HEADER_SUBSCRIPTIONID
	 *            SubscriptionId} header is missing.
	 * @return <code>Subscription</code> object in case the subscription was
	 *         successful.
	 */
	public Subscription subscribe(SubscriptionInfo info, String subscriptionId)
			throws DavException;

	/**
	 * Unsubscribe the event listener with the given SubscriptionId.
	 * 
	 * @param subscriptionId
	 *            as present in the
	 *            {@link ObservationConstants#HEADER_SUBSCRIPTIONID
	 *            SubscriptionId} header.
	 */
	public void unsubscribe(String subscriptionId) throws DavException;
}